I've thought about this a lot. The original question was about HS and possibly college. When my son was 7 he played with the local travel A team but it was a 7/8 split in the fall. The organization frowned on playing up so when it came time to try out for the spring/summer team he dropped down to his age group for try-outs. I was watching try-outs with the parents of one of his best friends from school and the dad looked at me and asked "why the f is he trying out with this group?" My son was tracking fly balls with ease and making plays other kids couldn't make. After the younger team try outs, he saw his buddies from the older team starting to arrive for their try outs. I asked my son what he wanted to do and he said he wanted to try out for the older Pirates. I told him it was on him. So my super shy 7 year old asked the commissioner if he could try out for the older team. Commish told him that two other players were more refined/prepared but that it was up to the coach. Kid walked up to the coach who welcomed him with open arms and the rest was history. He stayed with that team until his freshman year in HS. Local private schools started soft recruiting him in 4th grade.
Next flection point was in HS at WWBA 16U after his freshman year (14yrs old). They were at Lakepoint and he had three EV of 100+, the third one being a laser triple that he legged out. He competed well the whole tournament. That's when we knew for sure college was happening at some level.
Next one was East Coast Pro where he had two grand slams in back to back games. He was relatively unknown, playing with guys who were touted as the best players of his class and he wasn't overmatched. That's when we knew getting drafted out of HS was a possibility.
Each level of the minors is a jump and an adjustment. We honestly don't know how it will end but we think if he stays healthy he will have a shot.
So the short answer is at 7, almost 8 we knew he had unique abilities but each level (big field, puberty, HS, post HS) is a challenge so you don't really know until it actually happens. And in between there are injuries, slumps, coaches who didn't believe in him, people saying he was raw or doesn't work hard (because he has a laid back demeanor not because they have any idea what they are talking about)...and he continues to grind and work to be a smarter, stronger, more skilled version of the player he was the day before.
He definitely wrote in his 2nd grade yearbook that he was going to be a professional baseball player. 😂